Blood Vessels in a Mammal

• Capillary Diagrams

  A) Endothelial cell

  B) nuclei

  C) lumen

  D) Nucleus

  E) plasma

  F) erythrocyte

  G) 0.3

  
• Vein and Artery

  A) Tunica externa

  B) collagen

  C) elastic fibres

  D) Tunica media

  E) elastic

  F) collagen

  G) smooth muscle

  H) Tunica intima

  I) squamous layer of cells

  J) endothelium

  K) lumen

  L) lumen

  M) Tunica intima

  N) Tunica media

  O) Tunica externa

  
• Blood Vessels

  Artery:

  • Carry blood away from heart
  • Thick smooth muscle
  • Vasocontrict: reduce blood flow
  • Vasodilate: increase blood flow
  • Thick elastic (maintain pressure)
  • Arteriole: Smaller, similar wall

  Capillary:

  • Capillary beds in all tissue/organs
  • No elastic fibres, muscle, collagen or connective tissue
  • Single squamous endothelial layer
  • Porous wall; materials exchange, tissue fluid

  Vein:

  • Carry blood (low pressure) to heart
  • Between muscles and bones
  • Squeezed when muscle move
  • Semi-lunar valves prevent backflow when muscles relax
  • Venule: Smaller, same wall
• Mammalian Circulation

  • Closed circulatory system
  • Heart -> Artery -> Arterioles -> Capillaries -> Venules -> Vein -> Heart
  • Arteries and veins have same general structure but are tissue distribution differences